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Re: [TenTec] Orion Display and Power Distribution Board

To: tentec@contesting.com
Subject: Re: [TenTec] Orion Display and Power Distribution Board
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Reply-to: geraldj@weather.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Thu, 13 Jan 2011 11:14:19 -0600
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
If the BD246 wasn't faulty, just slowed by the length of the leads, how 
did the radio ever work? Might the aging of an electrolytic have 
contributed to the poor regulation?

73, Jerry, K0CQ

On 1/13/2011 7:59 AM, Heinz Dietmar Karl wrote:
> Thanks for the feedback.
> May I explain my impression that not the transistor BD246C itself is the
> problem.
> It was not defekt.
> Also not whether it was manufactured (see datasheed Bourns) . Yes the
> Datas between
> BD and Original NTE 378 are slightly different comparing the
> dynamics,switching times,
> dc current gain,  and I would in any case also prefer the Ten Tec design
> with the matched
> complementary transistors in the A9.
> The real problem was the different housing and because of this,
> the extern 8 cm -fare away -beside the board mounted one
> of these usualy pair of transistors (377and 378  in this switching mode
> supply).
> I had some luck to remembering myself to have worked 30years ago as an
> development member
> designing switchmode power supplies for ac drive inverters for a short time.
> best regards
> Heinz,DJ8LX
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